# Combining two 110-volt circuits

• 08-29-2009, 11:40 AM
Vince Rosati
Combining two 110-volt circuits
It is accepted practice (isn't it?) to split two 110-volt circuits from a three-conductor (red-white-black) into two 110-volt circuits.

I needed a 220-volt circuit to power a water pump in my shed. Running through the shed are two independent 110-volt lines. I tapped each "hot" wire to yield the 220 volts. (I installed a 2-pole breaker in the main panel to protect this arrangement). It works OK.

The question is: Am I violating the electrical code?

Thanks,

Vince Rosati
• 08-29-2009, 04:52 PM
Timothy Miller
Re: Combining two 110-volt circuits
Howdy call the local electrical inspector and ask he/she the code issue. Keep in mind the wire may not be large enough to bear the load depending on how long of run from your service panel and the size of the wire- eg . If it is 14/3 wire it is too light same with 12/3 most likely.... 10/3 less then 50' is ok.

Using a 3 wire for two circuits is used with the sharing of the neutral(usually) white wire. This is a less expensive way to run wire and less holes to make when running wire threw framing. Most common use is in kitchens for small appliance circuits running a 12/3 wire and playing hopscotch with which circuit for which receptacle.
• 08-29-2009, 08:12 PM
JLMCDANIEL
Re: Combining two 110-volt circuits
With a 3cond cable, you have basically run a 220 line to the shed. As long as the wire size matches the amperage protection you are code compliant.
Jack
• 08-30-2009, 10:34 AM
Vince Rosati
Re: Combining two 110-volt circuits
Thanks for the replies, but I guess I didn't state the case correctly.

Instead of running a 220-volt circuit using three conductor cable from the main panel and tapping off two 110-volt circuits in the shed, I did the opposite.

That is, there are two separate 110-volt circuits running from the main panel to/through the shed. The two 110-volt circuits are from different lugs in the main panel, such that out in the shed I measure 220 volts between the black wires of the two circuits.

I power the 220-V motor from those two hot wires (with a grounding conductor). (Four amps, by the way.)

Is this a violation of NEC?

Vince
• 08-30-2009, 09:57 PM
JLMCDANIEL
Re: Combining two 110-volt circuits
You have a 220 service to the shed, a single double pole breaker. It doesn't matter if you run 3 cond, 4 cond, or 20 cond and shared common circuits are also legal. You should be just fine as long as the smallest sized wire ampacity matches the breaker size.
Jack
• 08-30-2009, 10:10 PM
Vince Rosati
Re: Combining two 110-volt circuits
JL,

Great! That's the answer I was hoping for. When you said "3 conductor, 4 conductor, ..." I understood.

Thanks very much.

Vince